Class B_with_dict_weakref

Lib/test/test_descr.py:4237–4238

        self.assertEqual(repr(b), r)

        class B_with_dict_weakref:
            pass
        b = B_with_dict_weakref()
        with self.assertRaisesRegex(TypeError, 'layout differs'):
            B.__bases__ = (A_with_slots,)